The present invention relates to construction of metal buildings and more particularly to placing metal panels on the roof of such a building in a short time and with greater safety to roofing personnel.
Metal buildings are used for storage, industry and increasingly for residential purposes. These buildings often comprise a metal form of post and beam construction with rafters defining a pitched roof skeleton. Purlins of Z-form cross section are placed over the rafters and run the length of the building. The top bars of the purlins provide a base for supporting roofing panels which are elongated metal sheets running perpendicular to the direction of elongation of the purlins. Large packs of metal panels, typically comprising 20-30 sheets in a pack, are lifted onto a roof by a crane and roofing laborers carry one sheet at a time along the length of the roof to set down in a series array. In high winds, the panels can act as sails with danger of loss of panels and injury to personnel. Even in the absence of wind, it is difficult to maintain safe footing while walking along outer most purlins at the ridge and gutter extremities of a pitched roof while carrying a panel. Efforts in the art to provide safety straps or harnesses for workers have been too cumbersome and have failed to solve the safety problem.
It is an important object of the present invention to provide a safe roofing system.
It is a further object of the invention to provide greater speed, and consequently lower labor costs in connection with roofing metal buildings consistent with the foregoing object.
It is a further object of the invention to reliably transport a large number of roofing panels on the length of a building frame without binding or track jumping consistent with one or more of the preceding objects.
It is a further object of the invention to achieve the foregoing objects while simultaneously straightening out curves and misalignments in the purlins of the roofing structure.